Recruitment of endogenous mesenchymal stem cells (MSCs) has become an attractive strategy for in situ tissue regeneration. However, it is of great importance to endow an implant with a specific affinity to MSCs, for many types of cells such as immune cells and fibroblasts can also be recruited. It has been demonstrated that E7 peptides have a specific affinity to MSCs, but their selectivity for MSCs when co-cultured with other cells, especially in flow conditions, has rarely been investigated. In this study, E7-modified collagen substrates were prepared using sulfosuccinimidyl 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (sulfo-SMCC) as the coupling agent. The results of X-ray photoelectron spectroscopy (XPS) and quartz crystal microbalance (QCM) proved that the densities of the immobilized E7 peptides could be modulated by changing the amounts of sulfo-SMCC. The results of cell adhesion rate, adhesion area and adhesion force demonstrated that the immobilization of E7 peptides led to a significant enhancement of the adhesion of bone marrow-derived MSCs (BMSCs) compared to RAW264.7 cells and NIH3T3 cells. The selective adhesion was verified by co-culturing BMSCs with RAW264.7 cells and NIH3T3 cells, which indicated that higher proportions of BMSCs were adhered on the E7-immobilized substrates. By mimicking in vivo flow circumstances, the selective capture of BMSCs by the E7-modified substrates was revealed by a flow model. All these results suggest that E7 immobilization might be a promising strategy for an implant to achieve a better regeneration outcome by enhancing the affinity to the recruited MSCs.

中文翻译：

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在流动情况下选择性捕获成纤维细胞之间的间充质干细胞和E7修饰的胶原基质上的免疫细胞†

内源性间充质干细胞（MSCs）的招募已成为原位组织再生的一种有吸引力的策略。但是，赋予植入物对MSC特定的亲和力非常重要，因为还可以募集许多类型的细胞，例如免疫细胞和成纤维细胞。已经证明E7肽对MSC具有特异性亲和力，但是很少与其他细胞共培养时，特别是在流动条件下，其对MSC的选择性。在这项研究中，使用磺基琥珀酰亚胺4-（N-马来酰亚胺基甲基）环己烷-1-甲酸（磺基SMCC）作为偶联剂。X射线光电子能谱（XPS）和石英晶体微量天平（QCM）的结果证明，固定的E7肽的密度可以通过改变磺基-SMCC的量来调节。细胞粘附率，粘附面积和粘附力的结果表明，与RAW264.7细胞和NIH3T3细胞相比，E7肽的固定化显着增强了骨髓来源MSC（BMSC）的粘附性。通过将BMSC与RAW264.7细胞和NIH3T3细胞共培养来验证选择性粘附，这表明更高比例的BMSC粘附在固定了E7的底物上。通过模仿体内在流动情况下，通过流动模型揭示了E7修饰的底物对BMSC的选择性捕获。所有这些结果表明，E7固定化可能是植入物通过增强与募集的MSC的亲和力以获得更好的再生结果的一种有前途的策略。